#include <iostream>

using namespace std;

int ack(int m, int n){
    if (m == 0)
        return n + 1;
    else if (m != 0 && n == 0)
        return ack(m-1, 1);
    else if (m != 0 && n != 0)
        return ack(m-1, ack(m, n-1));
}
int main()
{
    cout << ack(2, 1);
}
